General Pathology Practice Questions

Q: Iron in tissues is stained with which of the following stains?

Prussian Blue. **Explanation:** **Prussian Blue (Perls' Stain)** is the correct answer because it is the gold-standard histochemical stain used to detect **ferric iron (Fe³⁺)** in tissues [1]. The underlying chemical principle involves the reaction of ferric iron with potassium ferrocyanide in an acidic medium, resulting in the formation of a bright blue pigment called ferric ferrocyanide (Prussian Blue). This stain is primarily used to visualize iron stored in the form of **hemosiderin** within macrophages (siderophages) or parenchymal cells [1]. **Analysis of Incorrect Options:** * **Sudan O (Sudan III/IV):** These are lipid-soluble dyes used to stain **neutral fats (lipids)** and triglycerides. They are commonly used on frozen sections to diagnose fat embolism or steatosis. * **PAS (Periodic Acid-Schiff):** This stain detects **glycogen** and mucopolysaccharides. It is widely used to visualize basement membranes, fungal walls, and glycogen storage diseases. **Clinical Pearls for NEET-PG:** * **Hemochromatosis vs. Hemosiderosis:** Prussian Blue is essential for grading iron overload in the liver and heart [1]. * **Sideroblastic Anemia:** This stain identifies "Ringed Sideroblasts" in the bone marrow (iron-laden mitochondria surrounding the nucleus). * **Heart Failure Cells:** In chronic passive congestion of the lungs, Prussian Blue identifies hemosiderin-laden macrophages in the alveoli. * **Note:** It does **not** stain iron in hemoglobin or ferritin directly; it specifically targets the insoluble hemosiderin. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 854-855.

Q: A ring chromosome is a result of which chromosomal abnormality?

Deletion. **Explanation:** A **ring chromosome** is a structural chromosomal abnormality that occurs when a chromosome undergoes **terminal deletions** at both the short (p) and long (q) arms. Following the loss of these distal segments, the remaining "sticky" ends of the central portion fuse together to form a ring shape. Because the formation of a ring chromosome necessitates the loss of genetic material from the telomeric regions, it is fundamentally a result of **deletion**. **Analysis of Options:** * **A. Deletion (Correct):** As described, the breakage of both ends of a chromosome followed by fusion is the mechanism. The resulting loss of genetic material often leads to clinical phenotypes (e.g., Ring 20 syndrome). * **B. Inversion:** This involves a single chromosome undergoing two breaks, with the intervening segment rotating 180° and reinserting. There is no loss of genetic material (balanced). * **C. Duplication:** This refers to the presence of an extra copy of a segment of a chromosome. * **D. Translocation:** This involves the exchange of segments between non-homologous chromosomes (e.g., Robertsonian or Reciprocal translocations). **High-Yield NEET-PG Pearls:** * **Karyotype Notation:** A ring chromosome is denoted by the symbol **'r'** (e.g., 46,XX,r(15)). * **Clinical Significance:** Ring chromosomes are often unstable during mitosis, leading to mosaicism [2]. * **Common Example:** **Ring 14 syndrome** (characterized by seizures and intellectual disability) and **Ring X** (a variant of Turner Syndrome) [1]. * **Telomeres:** Normally, telomeres prevent end-to-end fusion; ring formation only occurs when telomeres are lost via deletion. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 175-177. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 168-169.

Q: Which of the following is an execution caspase?

Caspase 3. Apoptosis (programmed cell death) is mediated by a family of cysteine proteases called **Caspases** [1]. These are broadly categorized into **Initiator caspases** and **Executioner (Effector) caspases**. **1. Why Caspase 3 is Correct:** Caspase 3 is the primary **Executioner Caspase**. Once activated by initiator caspases, executioners (Caspases 3, 6, and 7) cleave structural proteins and activate nucleases (like CAD - Caspase Activated DNase), leading to the characteristic morphological changes of apoptosis, such as DNA fragmentation and cell shrinkage. **2. Analysis of Incorrect Options:** * **Caspase 8:** This is an **Initiator Caspase** for the **Extrinsic (Death Receptor) Pathway** [1]. It is activated by the binding of ligands like FasL to the Fas receptor. * **Caspase 9:** This is an **Initiator Caspase** for the **Intrinsic (Mitochondrial) Pathway** [1]. It is activated when Cytochrome C is released into the cytosol and forms the "Apoptosome" complex. * **Caspase 5:** This belongs to the **Inflammatory Caspase** group (along with Caspases 1, 4, and 11), which are involved in pyroptosis and cytokine processing rather than the standard apoptotic cascade [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Initiator Caspases:** 8, 9, 10. * **Executioner Caspases:** 3, 6, 7. * **Intrinsic Pathway Marker:** Cytochrome C release from mitochondria [1]. * **Extrinsic Pathway Marker:** Activation of Caspase 8 (which can also cross-talk with the intrinsic pathway via the protein **Bid**). * **DNA Laddering:** A hallmark of apoptosis caused by internucleosomal cleavage of DNA by Caspase-activated nucleases. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 64-69.

Q: Which of the following stains is used to study fungal morphology in tissue sections?

PAS. **Explanation:** **Periodic Acid-Schiff (PAS)** is the correct answer because it is one of the most widely used special stains for demonstrating fungi in tissue sections. * **Mechanism:** Fungal cell walls are rich in polysaccharides (like chitin and glucan). Periodic acid oxidizes these carbohydrates to form aldehydes, which then react with the Schiff reagent to produce a brilliant **magenta/purplish-red** color. This provides excellent contrast against the tissue background, allowing for the identification of hyphae, spores, and yeast forms. **Analysis of Incorrect Options:** * **Von Kossa:** This stain is used to detect **calcium deposits** (mineralization) in tissues. It stains calcium salts black. * **Alizarin Red S:** Another specialized stain for **calcium**, often used to identify calcium oxalate crystals or bone mineralization. It produces an orange-red lake. * **Masson’s Trichrome:** This is a connective tissue stain used to differentiate between **collagen fibers** (blue/green) and muscle/cytoplasm (red). It is commonly used in liver and kidney biopsies to assess fibrosis. **High-Yield Clinical Pearls for NEET-PG:** * **Gomori Methenamine Silver (GMS):** Considered the "Gold Standard" for fungi; it stains fungal elements **black** against a green background. * **Mucicarmine:** Specifically used to identify *Cryptococcus neoformans* by staining its polysaccharide capsule **bright red**. * **India Ink:** Used for rapid identification of *Cryptococcus* in CSF (negative staining). * **Calcofluor White:** A fluorescent stain that binds to chitin; it is the most sensitive method for direct microscopic examination of fungal elements.

Q: Which of the following is seen in both apoptosis and necrosis?

May be pathological. ### Explanation The fundamental distinction between **apoptosis** (programmed cell death) and **necrosis** (accidental cell death) lies in their mechanisms and triggers. **1. Why "May be pathological" is correct:** Both processes can occur as a result of disease or injury [1]. * **Necrosis** is *always* pathological, resulting from irreversible exogenous injury (e.g., ischemia, toxins, or trauma). * **Apoptosis** is often physiological (e.g., embryogenesis, endometrial breakdown), but it can also be **pathological**. Pathological apoptosis occurs when cells are damaged beyond repair without causing a massive inflammatory response, such as in DNA damage (radiation/chemotherapy), accumulation of misfolded proteins (neurodegenerative diseases), or certain viral infections (e.g., viral hepatitis forming Councilman bodies) [1]. **2. Why other options are incorrect:** * **A. May be physiological:** This applies **only to apoptosis**. Necrosis is never a normal biological process; it is always a consequence of a harmful stimulus. * **C. Inflammation:** This is a hallmark of **necrosis** [1]. In necrosis, the cell membrane ruptures, releasing intracellular contents that trigger an inflammatory response. Apoptosis does not elicit inflammation because the cell contents are neatly packaged into apoptotic bodies. * **D. Intact cell membrane:** This is a feature of **apoptosis**. In necrosis, the loss of membrane integrity is a defining early event, leading to enzymatic leakage. ### NEET-PG High-Yield Pearls * **Councilman Bodies:** Eosinophilic apoptotic globules seen in the liver during Viral Hepatitis. * **Caspases:** The executioner enzymes of apoptosis (Cysteine proteases). * **Mitochondria:** The "central powerhouse" for the intrinsic pathway of apoptosis (releasing Cytochrome c). * **Pyknosis $\rightarrow$ Karyorrhexis $\rightarrow$ Karyolysis:** The classic sequence of nuclear changes seen in necrosis.

Question 1

Iron in tissues is stained with which of the following stains?

Accepted Answer

Prussian Blue

Answer

Sudan O

Answer

PAS

Answer

None of the above

Question 2

A ring chromosome is a result of which chromosomal abnormality?

Accepted Answer

Deletion

Answer

Inversion

Answer

Duplication

Answer

Translocation

Question 3

An embolus which passes through an arteriovenous communication and enters the systemic circulation is called?

Accepted Answer

Paradoxical embolus

Answer

Retrograde embolus

Answer

Saddle embolus

Answer

Atheroembolus

Question 4

Which of the following is an execution caspase?

Accepted Answer

Caspase 3

Answer

Caspase 5

Answer

Caspase 8

Answer

Caspase 9

Question 5

All of the following are transcription factors activated by signal transduction pathways of hypertrophy, except?

Accepted Answer

MLL1

Answer

GATA4

Answer

NFAT

Answer

MEF2

Question 6

Which of the following stains is used to study fungal morphology in tissue sections?

Accepted Answer

PAS

Answer

Von-kossa

Answer

Alizarin Red

Answer

Masson's Trichrome

Question 7

Which of the following is seen in both apoptosis and necrosis?

Accepted Answer

May be pathological

Answer

May be physiological

Answer

Inflammation

Answer

Intact cell membrane

Question 8

What is the chance of having cystic fibrosis if only one parent is affected and the other is normal?

Accepted Answer

50%

Answer

25%

Answer

70%

Answer

80%

Question 9

A 40-year-old female patient complains of breathlessness. She was operated for a femur fracture and is in her third trimester of pregnancy. Which type of embolism is most probably present in this patient?

Accepted Answer

Fat embolism

Answer

Air embolism

Answer

Amniotic fluid embolism

Answer

Cholesterol embolism

Question 10

A post-mortem clot is most likely to:

Accepted Answer

Grossly have the appearance of “chicken fat” overlying “currant jelly”

Answer

Grossly display features of recanalization

Answer

Grossly have lines of Zahn

Answer

Microscopically appear attached to the wall of the blood vessel

General Pathology — MCQs

General Pathology — MCQs

On this page

Practice by Chapter

Want unlimited practice?